How is PE Diagnosed? – Blood Clots

A number of different things may alert a physician that a person may be experiencing a pulmonary embolism, or blood clot in their lung.  When this is suspected, a number of crucial tests may be performed, including:

Pulse Oximetry

Often, the first test performed when PE is suspected is a blood oxygen level. The simplest way to measure the blood oxygen level is with a pulse oximeter. Pulse oximetry is a noninvasive way (does not involve a blood draw or needle stick) to monitor the percentage of hemoglobin that is saturated with oxygen. Hemoglobin is the unique molecule in red blood cells that has the ability to carry oxygen.

The pulse oximeter consists of a probe or sensor plus a computer. The probe, which looks like a padded clothespin, is placed on a relatively thin part of a person’s body, such as a finger or earlobe. Both red and infrared light are then transmitted through the tissue by the probe. Based on the absorption of the red and infrared light caused by the difference in color between hemoglobin that is saturated with oxygen (red) and unsaturated hemoglobin (blue), the computer can estimate the proportion of hemoglobin that is oxygenated. The pulse oximeter then displays this result as a percentage. A blood oxygen saturation level less than 95 percent is abnormal. It may be explained by a lung or heart problem already present, such as emphysema or pneumonia, or by PE (or both).

Arterial Blood Gas

A more precise measurement of blood oxygen level is obtained from a sample taken directly from an artery with a needle or a thin tube (catheter). An arterial blood gas (ABG) measures the levels of both oxygen and carbon dioxide in the blood to determine how well the lungs are working. While most blood tests are performed on samples taken from a vein, an ABG is performed on a sample taken from an artery. In most cases, the artery in the wrist is used for this purpose, but other arteries may be used. The levels of blood gases are measured as partial pressures in units of millimeters of mercury (mm Hg). A partial pressure of oxygen less than 80 mm Hg is abnormal.

Chest X-Ray

A chest x-ray cannot prove that PE is present or absent because clots do not show up on x-ray. Nevertheless, a chest x-ray is a useful test in the evaluation for PE because it can find other diseases, such as pneumonia or fluid in the lungs, that may explain a person’s symptoms. Occasionally, when pulmonary infarction occurs, the x-ray may suggest this diagnosis, although more testing is necessary to prove it with certainty. A normal or negative chest x-ray with a low, otherwise unexplained blood oxygen level, however, raises the suspicion for PE.

Ventilation-Perfusion Scan (VQ Scan)

A VQ lung scan may be a useful test to determine whether a person has experienced PE. This test evaluates both air flow (V = ventilation) and blood flow (Q = perfusion) in the lungs. About one hour before the test, a slightly radioactive version of the mineral technetium mixed with liquid protein is administered through a vein to identify areas of the lung that may have reduced blood flow. Multiple images are taken from different angles, using a special camera that detects radioactivity. For half of the images, the person breathes from a tube that contains a mixture of air, oxygen, and a slightly radioactive version of the gas xenon, which reveals air flow in different parts of the lung. For the other half of the images, the camera tracks the technetium, which reveals blood flow in different parts of the lung. PE is suspected in areas of the lung that have significant “mismatches”—that is, good air flow but poor blood flow.

Except for the minor discomfort from having an intravenous catheter placed, a VQ lung scan is painless and usually takes less than an hour. The exposure to radioactivity from the test is very minor and results in no side effects or complications.

A radiologist interprets the images from the VQ lung scan and decides whether the probability of a PE is high, low, or intermediate. If the probability is high, the diagnosis is made. If the probability is low or intermediate (that is, nondiagnostic), or if the VQ scan cannot be interpreted clearly, other testing must be considered. Even when PE is ultimately proven to be present, the VQ scan may be nondiagnostic. If clinical suspicion is low and the VQ scan reveals a low probability of PE, generally no further testing is needed. A normal VQ scan means PE is not present.

Spiral Computed Tomography of the Chest

An alternative to the VQ scan is a spiral computed tomography (CT) of the chest. A spiral CT of the chest uses special equipment to obtain multiple cross-sectional x-ray images of the organs and tissues of the chest. CT produces images that are far more detailed than those available with a conventional x-ray. Many different types of tissues—including the lungs, heart, bones, soft tissues, muscles, and blood vessels—can be seen.

When PE is suspected, contrast dye (usually iodine dye) is administered through a vein to make the blood vessels stand out.

During the spiral CT, radiation is emitted from a rotating tube. Different tissues absorb this radiation differently. During each rotation, approximately 1,000 images are recorded, which a computer then reassembles to produce a detailed image of the interior of the chest. The x-ray rotates as the patient passes through the CT scanner in a spiral path—hence the term “spiral” CT. The amount of radiation exposure is relatively low, and the procedure is not invasive.

Pulmonary Angiogram

If the VQ scan interpretation is low, intermediate, or uncertain probability of PE, or if the spiral CT is normal yet the symptoms are still suspicious, then the definitive test is a pulmonary angiogram.  An angiogram is an invasive test that uses x-rays to reveal blockages or other abnormalities within the veins or arteries. Contrast dye (usually iodine dye) helps blood vessels show up clearly on x-rays. During an angiogram, contrast dye is injected into a blood vessel, and its path is tracked by a series of x-rays.

A pulmonary angiogram examines the arteries that carry blood from the heart to the lungs and is performed to see if PE is present. Using x-rays in real-time (fluoroscopy), the radiologist inserts a catheter into a vein and advances it until it reaches the vena cava (the very large vein that carries blood to the heart). Next, the radiologist advances the catheter still farther into the right side of the heart and finally into the pulmonary artery, the large artery that carries blood to the lungs. The radiologist directs the tip of the catheter into the different branches of the right and left pulmonary arteries and injects the contrast dye, which illuminates the arteries on x-ray. If PE is present, it will show up as a blockage.

Risks associated with a pulmonary angiogram include the possibility of damage caused by the catheter, bleeding, and an allergic reaction to the contrast dye. The amount of radiation from the x-rays is too small to cause any harm.

Echocardiogram

An echocardiogram is an ultrasound of the heart. Doppler ultrasound, B-mode ultrasound, and M-mode ultrasound (a rapid sequence of B-mode images that allows motion to be visualized) are combined to give information about the size of the heart, the function of the valves, and the strength of the heart muscle. (Duplex ultrasound is discussed in detail in Question 9. ) The echocardiogram can spot areas of the heart that are not working well. When patients with a PE have an echocardiogram, approximately 40 percent will be found to have abnormalities of the right side of the heart, particularly the right ventricle. While an echocardiogram is not actually used to diagnose a PE, it can identify strain on the right side of the heart caused by a large PE as well as certain heart problems that may imitate a PE.

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Diagnosing Blood Clots | Imaging Tests Overview

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Angiography of thoracic aorta

Doppler ultrasonography is the most widely available noninvasive test for deep vein thrombosis.  

Diagnosing deep vein thrombosis and pulmonary embolism may be difficult as the signs and symptoms associated with these disorders are not unique to these conditions. For example, leg pain and swelling or chest pain and shortness of breath may have other causes. As a result, testing is needed to confirm the diagnosis.

Venography and pulmonary angiography remain the gold standards for diagnosis of deep vein thrombosis and pulmonary embolism respectively; however, these tests are now being increasingly replaced by less invasive and less expensive procedures. Three types of imaging tests may be used to diagnose clots in veins.

RADIO LABEL TESTS

Radioactive fibrinogen leg scanning is moderately sensitive and specific for clots in the calf and popliteal veins, but less sensitive for superficial clots in the femoral or iliac veins.

The AcuTect venogram test is a synthetic radiochemical that binds to a protein found on activated platelets. The AcuTect venogram is used to diagnose acute venous clots in the lower extremities of patients with signs and symptoms of such clots. The AcuTect appears to detect acute, but not chronic, clots in the veins.

ULTRASOUND TESTS

The doppler-augmented ultrasound and impedance plethysmography technique are sensitive to proximal clots that cause blockages. Impedance plethysmography does not detect calf vein clots or proximal vein clots that do not block the blood vessel.

Doppler ultrasonography is the most widely available noninvasive test for deep vein thrombosis. Doppler ultrasonography has become the dominant test since the 1980s and has largely replaced impedance plethysmography for noninvasive testing.

X-RAY AND COMPUTED TOMOGRAPHY TESTS

Venography testing can detect clots in both calf and proximal veins.

V/Q scanning may be used as a one-step method to diagnose pulmonary embolism in patients with a normal chest radiograph. In patients with an abnormal chest radiograph, V/Q scanning should be used in combination with helical spiral computed tomography testing. V/Q scans tend to be used mainly to exclude rather than confirm pulmonary embolism. V/Q scanning is able to show small clots–and this ability is enhanced by single photon emission computed tomography.

The helical spiral computed tomography technique is very effective in diagnosing clinically important pulmonary embolism and a large number of alternative diagnoses in patients with symptoms who have undergone a V/Q scan. This is an accurate method for detecting and excluding most types of pulmonary embolism.

Laboratory testing is another method of diagnosis

• What is a Blood Clot?
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Intracardiac thrombi. Diagnosis and treatment

Blood clots can form not only in veins, but also in heart cavities and arteries.

Blood clots are a natural reaction of the body. They contribute to the restoration of damaged blood vessels. A blood clot is a blood clot that contains fibrin (a protein needed for blood clotting). But blood clots in the cavities of the heart is a completely different matter.

The most dangerous thing is that there are no symptoms by which one can suspect the presence of intracardiac thrombi. It is possible to detect a thrombus in the cavities of the heart only during diagnostics (echocardiography, etc.). And any symptoms (shortness of breath or suffocation) a person can only feel with pulmonary embolism.

Thrombi can be in the left or right cavities of the heart, in the atria or ventricles (more often these are parietal thrombi).

What are blood clots:

• Floating. These are partially attached thrombi. The danger is that the floating part of the thrombus may come off;
• Parietal, when the clot is completely attached to the wall of the chamber of the heart;
• Occlusive. The most dangerous! These clots cut off blood flow.

Thrombi in the left side of the heart

Most often, blood clots in the left cavities of the heart occur against the background of three diseases.

People at risk are:

• with mitral valve stenosis;
• with atrial fibrillation (atrial fibrillation):
• with postinfarction aneurysm of the left ventricle.

Blood clots in the left side of the heart – the risk of arterial thromboembolism, ischemic attacks or cerebral infarction! With the localization of blood clots in the left cavities of the heart, the arteries of the kidneys, upper and lower extremities, and the arteries of the intestine can also be affected.

Heart attacks and strokes

In arterial atherosclerosis and plaque rupture, a blood clot forms in the artery. As a result, myocardial infarction (necrosis of the organ tissue) can occur. If a thrombus located in the cavity of the left ventricle breaks off, then, spreading through the blood stream, it can clog the arteries of the brain (as a result, cerebral infarction occurs – ischemic stroke), kidneys (kidney infarction), intestines (intestinal infarction, mesenteric thrombosis), limbs (gangrene).

If a clot breaks off, it can spread with the bloodstream and close the vessel lumen! When the vessel is blocked, blood circulation is disturbed, which leads to oxygen starvation and tissue necrosis. This can cause complications such as myocardial infarction, PE, and even death.

If there is an open oval window in the intercardiac septum, blood clots from the veins of the lower extremities, the pelvis can move from the right atrium to the left and then enter the brain with the blood flow. The result is also a stroke.

Blood clots resulting from an aneurysm of the heart

After a heart attack, parietal thrombi may form in the left ventricle. They are seen by specialists with the help of echocardiography. This is the main type of diagnostic for the detection of blood clots in the cavities of the heart. If they are detected, a specialist may prescribe anticoagulants (in the absence of contraindications).

Thrombi formed during mitral valve stenosis

There is a special variety – a spherical thrombus in the left atrium. Such a thrombus is formed during mitral valve stenosis, in which outflow from the left atrium into the left ventricle is disturbed.

Thrombi formed during atrial fibrillation (atrial fibrillation)

In atrial fibrillation, blood clots are usually localized in the left atrial appendages. The ear is a protrusion of the atrium (it looks like a sac). Thrombi of the left atrial appendage can be detected most often only with transesophageal echocardiography. They are very difficult to detect with echocardiography.

Blood clots in the right side of the heart

The presence of a blood clot in the right side of the heart is fraught with complications in the form of thromboembolism of the branches of the pulmonary artery (a disease in which the arteries of the lungs are affected). PE is one of the most dangerous complications.

A thrombus may first form in the deep veins of the lower extremities. If a floating thrombus breaks off, then with the blood flow it first enters the right heart, and then into the pulmonary artery. This can lead to sudden death!

Diagnosis

The main method for diagnosing intracardiac thrombi in MedicCity is echocardiography.

1

Echo-KG (ultrasound of the heart)

2

Echo-KG (ultrasound of the heart)

3

Echo-KG (ultrasound of the heart)

If you need to diagnose blood clots in the veins, duplex scanning of the veins of the lower extremities is performed, etc.

Treatment

To prevent thrombosis, a specialist may prescribe you anticoagulants or antiaggregants (if there are no contraindications).

Patients with mitral valve stenosis, atrial fibrillation or postinfarction aneurysm need regular echocardiographic monitoring! Especially in the presence of prosthetic valves. In this case, ECHO-KG should be done every year.

After a myocardial infarction, it is necessary to check whether a blood clot has formed in the cavity of the heart.

Those who take hormonal contraception are also at risk. They increase the risk of thrombosis, as well as myocardial infarction. You may find a warning in the instructions for the side effects.

Intracardiac clots can lead to serious complications! If necessary, consult a doctor and follow all recommendations.

The material was prepared with the participation of a specialist:

• Zakharov Stanislav Yurievich

  Cardiologist, doctor of functional diagnostics

  Highest qualification category, Doctor of Medicine, Member of the European Society of Cardiology and the Russian Society of Cardiology

7 signs that there may be blood clots in the body

Likbez

Health

April 24, 2021

If you do not seek help in time, you can say goodbye to life.

Blood clots are clotted blood. Normally, they protect us from scratches and other wounds: blood coagulates, a clot stops bleeding from a damaged capillary or vein. And then, having completed the task, within a few hours or days, it safely disintegrates and disappears. But sometimes things don’t go according to plan.

Why blood clots are dangerous

Blood clots can also occur inside the veins. This condition is called thrombosis. It most often affects the legs, especially if you lead a sedentary lifestyle. But any part of the body can be at risk.

If such a blood clot breaks off, it enters the general circulation and can clog vessels in the heart, brain or lungs. This is a life-threatening situation that can lead to a heart attack, stroke, or pulmonary embolism, the stoppage of the lungs.

Therefore, it is extremely important to know the symptoms that blood clots manifest themselves in. Your life may depend on it.

Reading now 💔

• 11 signs you may be in cardiac arrest

When to call an ambulance immediately

Urgently dial 103 or 112 if:

• it suddenly becomes difficult to breathe, there is a lack of oxygen;
• present with chest pain or simple discomfort that is aggravated by coughing or taking a deep breath;
• coughing up bloody sputum;
• difficulty speaking;
• eyesight worsened – vision began to double, blind spots appeared, “fog”;
• blood pressure dropped sharply, and this is accompanied by dizziness, clouding of consciousness, fainting.

This is how a heart attack, stroke, pulmonary embolism manifest themselves. It is not a fact that they are provoked by a detached thrombus. But in any case, there is no time to think about the reasons: if the above symptoms appear, immediately seek help.

How to understand that you may have blood clots

It is better not to bring things to critical, deadly manifestations – this is already clear. Thrombosis is important to catch at the earliest possible stage in order to prevent complications.

The problem is that it is difficult to suspect the presence of blood clots in the vessels. According to the US Centers for Disease Control and Prevention, in about half of people, blood clots almost never show themselves.

Nevertheless, it is still possible to assume blockage of blood vessels. Here are a few signs that indicate a possible thrombosis in different parts of the body.

1. Swelling in the leg or arm

Swelling can either occur in the place where the vessel is directly blocked, or spread to the entire limb. Moreover, in this case, only one arm or leg suffers – the one in the vessels of which the alleged blood clot is located.

2. Leg cramps

Regular cramps can be a symptom of circulatory problems. Blood clots can also cause it.

3. Sudden pain in the leg

This is one of the main symptoms of deep vein thrombosis. Often pain in the calf muscle, sharp or pulsating, is almost the only sign of acute circulatory disorders.

4. Changes in skin color

Blood clot impedes normal blood circulation. As a result, some of the blood vessels are overflowing with blood, while others, on the contrary, suffer from a lack of it. This can be manifested by changes in skin color: in some areas of the affected limb, it turns red or becomes cyanotic, in others, on the contrary, it turns pale.

5. Changes in skin temperature

The skin around the blood clot may be regularly warm and itchy. An increase in temperature is a chance to feel to the touch.

6. Unmotivated attacks of nausea or vomiting

If you feel nauseated regularly, this may be a symptom of thrombosis of the mesenteric vessels – those that supply blood to different parts of the intestine. You can assume the condition if vomiting appears, but does not bring relief, and you continue to feel nauseous.

7. Abdominal pain

It can also be a sign of obstruction of the mesenteric vessels. Especially if the stomach aches almost constantly, and the pain intensifies after eating. Also among the indirect signs of thrombosis can be called diarrhea and bloating.

What to do if you have signs of thrombosis

If you have the slightest suspicion, be sure to consult a physician as soon as possible. The doctor will conduct an examination, ask you about the symptoms and, if necessary, send you to a narrow specialist – a phlebologist or a vascular surgeon.

Treatment will depend on where the clot is located and how likely it is to break off.